East wind - the last line of winter's defense...
Posted January 11th, 2013 by Bill Kardas. 40 comments
First, some stats of our current January thaw-
7 days in a row above freezing & counting
(longest streak in recent memory was 9 days back in 2008)
7 days in a row without measurable snowfall & counting
(longest streak in recent memory was 11 days also in 2008)
These are impressive numbers for January. Our thaw isn't done yet as we continue to add more days to this tally. It won't be smooth sailing though...
RETURN OF THE EAST WIND
Ah yes, the notorious east wind makes a return to Central New York today. The east wind is an ageostrophic wind caused by local topography. Ageostrophic is a fancy term that basicially translates to 'what the wind would naturally do without the coriolis force, or rotation of the earth). Wind naturally wants to move from high pressure to low pressure. The coriolis force bends the wind to the right of this motion. That's why low's rotate counterclockwise and highs rotate clockwise.
How do we elimate the coriolis force? Well, we don't eliminate it because we can't stop the earth from spinning, but we can overcome that force by adding friction. Friction due to hilly terrain causes winds to bend into the east under the right pressure conditions. In our case, when high pressure is located east and low pressure to the west, the east wind is strongest.
Why is the east wind cold if it's blowing from the east? Good question. In order to answer that, we have to understand local topography's influence on weather. Take a look at a topographic map of NYS. You'll notice several 'north/south' oriented valleys connecting the Mohawk River to the Adirondack drainage basin. Cold air that builds in the Adirondacks will naturally drain down these valleys into the Eastern Mohawk Valley. Areas from Canajoharie east are slightly climatologically colder year round due to this effect. An east wind brings that cold air west, something called cold air advection.
Extent & overall effect of the east wind
The east wind gets a bad reputation around here, but in reality it acts more like a 'last line of defense' for snow lovers. It's important to point out that this effect only happens when warm air is on the way. The extent of the east wind depends on the scenario. Many times, the east wind effect extends to Rome. In most cases it serves to delay *not prevent* a warmup. The only exception to that rule is areas from Canajoharie east (as mentioned above).
Freezing rain events are more common due to the east wind. There is a climatological 'spike' in freezing rain occurances in the Mohawk Valley due to this localized effect. Today, we're confident enough to say that temperatures ought to climb above freezing before our rain event moves in, but we will certainly keep tabs on the east wind. We've seen many surprises in past years.
The good news is that the east wind can't maintain the cold forever. Once upper level winds get strong enough, the cold air gets 'scoured out' of the valleys, and temperatures warm up a lot. Even under ideal conditions, the east wind breaks down after about 24-36 hours. While the east wind keeps us in the 30s for most of today, we'll easily climb into the 40s by Saturday and 50s on Sunday.
Recent Comments on this Entry
- unwildgirl (Richfield Springs) January 12th, 4:04 PM
- Rob (Whitesboro) January 12th, 12:34 PM
- Adam Musyt January 12th, 12:21 PM
- nugfin (Neil) (South Utica - Genesee St.) January 12th, 12:10 PM
- Mel (Westernville) January 12th, 11:52 AM
- Rob (Whitesboro) January 12th, 11:34 AM
- Adam Musyt January 12th, 11:27 AM
- Bill Kardas (WKTV) January 12th, 11:07 AM
- Tim (Salisbury) January 12th, 9:22 AM
- nugfin (Neil) (South Utica - Genesee St.) January 12th, 8:54 AM
- How Doppler Radar is used to track tornadoes 3 days ago
- Late season widespread frost... 5 days ago
- Snow on Mother’s Day 7 days ago
- More Rain and a Weekend Cool Down May 9th, 2013
- Snoozecast May 5th, 2013
- Severe Weather Awareness Week April 30th, 2013
- Beautiful weekend ahead - & a helpful reminder... April 26th, 2013
- Mild weather & another round of storms... April 24th, 2013